Porous composite, bone regeneration material, and method for producing porous composite

Abstract

Provided are a porous composite containing OCP and collagen having higher compressive strength than before; a bone regeneration material containing the same; and a method for producing a porous composite. The porous composite contains octacalcium phosphate and collagen, has a pore size of 5 μm to 40 μm as determined by measurement using a mercury porosimeter, and contains pores of 71 μm to 200 μm at a rate of less than or equal to 8% in all pores of less than or equal to 200 μm.

The invention claimed is: 
     
       1. A porous composite, comprising:
 octacalcium phosphate and collagen, 
 wherein the octacalcium phosphate is present as granules in the porous composite, 
 wherein the porous composite comprises pores having a size of 5 μm to 40 μm, 
 wherein the pore size is a value of micropore diameter showing a maximum value of a peak having a largest area in a micropore distribution curve obtained by measuring pressure by a mercury intrusion method using a mercury porosimeter, 
 wherein a volume of pores having a size of 71 μm to 200 μm divided by a volume of all pores having a size of less than or equal to 200 μm, multiplied by 100, is less than or equal to 8% and more than 0%, and 
 wherein said porous composite has a compressive strength of greater than or equal to 0.3 MPa. 
 
     
     
       2. A bone regeneration material comprising the porous composite according to  claim 1 . 
     
     
       3. A method for producing a porous composite comprising octacalcium phosphate and collagen, comprising the steps of:
 (a) adding particles of octacalcium phosphate to a collagen solution, 
 (b) freezing a gel, sol or liquid containing octacalcium phosphate and collagen, and 
 (c) lyophilizing the frozen gel, sol or liquid, 
 wherein said porous composite has a compressive strength of greater than or equal to 0.3 MPa, and 
 wherein the freezing of step (b) is performed by dipping the gel, sol or liquid containing octacalcium phosphate and collagen in a liquid refrigerant. 
 
     
     
       4. The porous composite according to  claim 1 , wherein porosity of the porous composite is 80% to 98%. 
     
     
       5. The porous composite according to  claim 4 , wherein the granules include granules having a diameter of 10 μm to 1000 μm. 
     
     
       6. The porous composite according to  claim 5 , wherein the collagen forms a spongy structure. 
     
     
       7. The porous composite according to  claim 5 , wherein the granules include granules having a diameter of 300 μm to 500 μm. 
     
     
       8. The porous composite according to  claim 7 , wherein the collagen forms a spongy structure. 
     
     
       9. The porous composite according to  claim 7 , wherein ratio of octacalcium phosphate in the porous composite to 1 part by weight of collagen in the porous composite is 0.5 parts by weight to 35 parts by weight. 
     
     
       10. The porous composite according to  claim 9 , wherein the collagen forms a spongy structure. 
     
     
       11. The method for producing a porous composite according to  claim 3 , wherein the temperature of the liquid refrigerant is less than or equal to −20° C. 
     
     
       12. The method for producing a porous composite according to  claim 11 , wherein the liquid refrigerant is at least one selected from the group consisting of methanol, ethanol, acetone, acetonitrile, and liquid nitrogen. 
     
     
       13. The method for producing a porous composite according to  claim 12 , wherein the temperature of the liquid refrigerant is less than or equal to −40° C. 
     
     
       14. The method for producing a porous composite according to  claim 3 , further comprising, after steps (a)-(c), the step of:
 (d) subjecting the lyophilized product obtained by the step (c) to a heat treatment at 50° C. to 200° C. 
 
     
     
       15. The method for producing a porous composite according to  claim 11 , further comprising, after steps (a)-(c), the step of:
 (d) subjecting the lyophilized product obtained by the step (c) to a heat treatment at 50° C. to 200° C. 
 
     
     
       16. The method for producing a porous composite according to  claim 12 , further comprising, after steps (a)-(c), the step of:
 (d) subjecting the lyophilized product obtained by the step (c) to a heat treatment at 50° C. to 200° C. 
 
     
     
       17. The method for producing a porous composite according to  claim 13 , further comprising, after steps (a)-(c), the step of:
 (d) subjecting the lyophilized product obtained by the step (c) to a heat treatment at 50° C. to 200° C.